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Method of Producing Silicon Dioxide Layers with Uniform Thickness

IP.com Disclosure Number: IPCOM000051591D
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Schmitt, A: AUTHOR

Abstract

This invention is based on the concept that oxidation in dry oxygen yields particularly uniform oxide thicknesses if the silicon wafer, prior to oxidation, is cleaned at low temperature in an oxygen atmosphere, using an addition of halogenated hydrocarbons.

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Method of Producing Silicon Dioxide Layers with Uniform Thickness

This invention is based on the concept that oxidation in dry oxygen yields particularly uniform oxide thicknesses if the silicon wafer, prior to oxidation, is cleaned at low temperature in an oxygen atmosphere, using an addition of halogenated hydrocarbons.

Wafers are introduced into an oxidation tube which is scavenged with oxygen at 800 degrees C. At that temperature there is no noticeable oxidation of the silicon. The oxygen is led in part through a bubbler which is filled with a halogenated hydrocarbon (CCl(4), CHCl(3), C(2)H(3)Cl(3)). During this process, the oxygen is enriched. Tests have shown that an addition of at least 0.5 percent by volume of halogenated hydrocarbon is necessary and that in practice an addition of several volume per cent is advantageous for cleaning. After about 15 minutes, the supply of halogenated hydrocarbon is interrupted. The tube is heated to the oxidation temperature >/- 900 degrees C, and the wafers are oxidized for several minutes in dry oxygen.

Oxide thickness measurements by means of an ellipsometer show that at a total thickness from 10 to 100 nm the fluctuations in thickness do not exceed 3 to 4 percent. The method described is particularly suitable for growing a screen oxide prior to ion implantation, for which close tolerances are required.

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